cfg80211: fix for duplicate userspace replies
This fixes an incorrect assumption (BUG_ON) made in
cfg80211 when handling country IE regulatory requests.
The assumption was that we won't try to call_crda()
twice for the same event and therefore we will not
recieve two replies through nl80211 for the regulatory
request. As it turns out it is true we don't call_crda()
twice for the same event, however, kobject_uevent_env()
*might* send the udev event twice and/or userspace can
simply process the udev event twice. We remove the BUG_ON()
and simply ignore the duplicate request.
For details refer to this thread:
http://marc.info/?l=linux-wireless&m=124149987921337&w=2
Cc: stable@kernel.org
Reported-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index f87ac1d..ea4c299 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -2171,7 +2171,13 @@
* the country IE rd with what CRDA believes that country should have
*/
- BUG_ON(!country_ie_regdomain);
+ /*
+ * Userspace could have sent two replies with only
+ * one kernel request. By the second reply we would have
+ * already processed and consumed the country_ie_regdomain.
+ */
+ if (!country_ie_regdomain)
+ return -EALREADY;
BUG_ON(rd == country_ie_regdomain);
/*